As the size of a semiconductor device is reduced, it is required to form a wire pattern finer than the critical dimension of a resolution of lithography. A side wall transfer technique is known as one of such techniques for forming a fine wire pattern.
An end portion of a wire formed according to the side wall transfer technique is connected to a wire and the like of another layer, and therefore, it is necessary to provide a pad wider than the width of the wire. Such pad cannot be formed by only the side wall transfer technique. A technique for adding cover process for forming the pad is known.
The cover process is a process that includes forming a side wall pattern along an external periphery of a core material, thereafter covering, with a mask, a core material for a pad in an area where the pad is formed, and leaving the core material for the pad when the core material in the area where the wire is formed is removed. Thereafter, during etching, the core material for the pad serves as a mask, and a wide pad can be formed.